I feel that if you become the head of a great house or guild, the least everyone could do is grovel before your greatness. Instead, the only way you know you're the head of some of these guilds is to read your character sheet!

I can still remember the first time I became Archmage, and no one said anything to me. I kept peeking just to make sure I hadn't dreamed it!

if you didn't kill trebounius to become grandmaster in mage guild. he will give you a quest after you defeat dagoth ur.

hmm, I didn't know about that. I guess I'll go do those now ;)

Basically you're out of a job once you rule the guild, there simply isn't anything left to do for you. Just move on to the next guild.

yeah they should give you special stuff now and then, and have people do things for you, like quests and such